Beloit city officials said the emerald ash borer was found in an infested tree on LaSalle Street during the scheduled removal of the tree by city workers. The crew observed 1/8-inch-wide D-shaped holes, wood pecker damage and split bark.

"We always knew it was here we just hadn't found it," said Beloit Forestry Operations Supervisor Mike Ferger.

The positive identification was confirmed by the Wisconsin Department of Agriculture.

"We took it down, we looked it over real good, we found some galleries and some exit holes and tha''s when I turned it over to the DNR," Ferger said.

K & W Greenery in Janesville is helping homeowners worried about their trees.

"Now is the time to do it,” said nursery Manager Kyle Aurit. “Things are starting to wake up and actively start to grow." Do-it-yourself kits range from about $30 to $100 for larger trees and Aurit recommended calling in professionals like K & W to handle it for you.

Aurit said the treatment professionals use to treat trees protects them for two years, but the over-the-counter consumer products only protect for a year.

"If the tree is infected but you have at least 50 percent or more of the canopy the trees can be saved," Aurit said.

The EAB has destroyed millions of ash trees since being detected in North America. The beetle's larvae kill the host ash tree by tunneling through the soft wood just under the bark that supplies the tree with food and water.

Large, healthy trees can succumb to EAB within three to five years.

Beloit will begin treating other trees in an effort to save the city's estimated 2,200 ash trees from the silent killer.

Beloit residents concerned about the health of their ash trees should consult a local professional arborist, tree care specialist or call the Beloit Department of Public Works at 608-364-2929.

Rock County is under quarantine for the emerald ash borer. All hardwood firewood; ash products such as timber, pallets, mulch and trimmings; and ash nursery stock should not be moved out of the area.